Upstream for dtrace, opensolaris and zfs is Illumos. Note that ZFS generally follows Illumos development in a cherry-pick manner and not as a wholesale from certain release so the version here is usually outdated. Current ZFS on all supported branches are post-"Feature Flags", or also known as "version 5000".

Software also available someplace else (sibling projects)

These tools have been picked up by someone else, or are also available at a different location or in another BSD. They are not considered contrib source in our tree, but have substantial new development available elsewhere. They evolved from *BSD though, and we might want to cherry-pick changes and bring them into our tree, or migrate them to fully contrib software.

Notes on software with ceased upstream development

telnet: no new version has been imported in 14+ years. Maybe move to usr.bin/telnet as all "development", which is mainly security fixes, takes place in the FreeBSD svn repo. This is where telnet lives under OpenBSD, NetBSD and DragonFly BSD.